This invention relates to an air conditioning control system for controlling the operation of a group of air conditioners installed in a building, and more particularly to a control system of the kind described above which is suitable for controlling the operation of such an air conditioner group from a plurality of spots in the building.
Air conditioning control systems used hitherto for controlling the operation of a group of air conditioners installed in a building are broadly classified into two types. In one type of the air conditioning control system, the power, lighting equipments, elevators, air conditioners, etc. are collectively controlled by monitoring a central monitor board in the building, and the individual air conditioners are controlled to operate according to an operation control signal applied from the building's central monitor board. In this case, the operation control signal outputted from the building's central monitor board is transmitted to a relay located at a position remote from the central monitor board, and the relay acts to identify which air conditioner is to be controlled by what kind of the operation control signal, and the operation control signal is transmitted to the desired air conditioner to operate the air conditioner. In another type of the air conditioning control system, the operation of the individual air conditioners is controlled by an operation control signal inputted from a centralized air conditioner control unit installed in the building. In this case, the operation control signal from the centralized air conditioner control unit is identified by the centralized control unit itself to be transmitted to a desired air conditioner. Thus, the operation of the individual air conditioners can be controlled in the latter control system.
It will be seen from the above description that, in the case of the prior art air conditioning control systems controlling the air conditioner group, the operation of the air conditioner group was controlled at a single spot only in the building.
As the scale of the building becomes larger, it is apparent that the total number of the air conditioners installed in the building becomes also larger. In such a case, or when the operation of all of air conditioners installed in a plurality of buildings is to be collectively controlled from a single spot only, that is, for example, by a building's central monitor board installed in a control building, trouble occurring in the building's central monitor board will exert a great influence on the operation of the control system. Therefore, in such an event, it becomes necessary to minimize such an undesirable influence attributable to the trouble.
Another air conditioning control system is disclosed in JP-A-Sho61-202040. According to the disclosure of the cited application, each of individual air conditioners installed in a building is provided with a remote controller which is designed so as not to respond to an instruction signal from a central control unit, and each of the individual air conditioners is controlled to start and stop according to an instruction signal from the associated remote controller.
However, in the case of the control system disclosed in the cited application, each of the individual air conditioners cannot be controlled from the central control unit because the associated remote controller is designed so as not to respond to the instruction signal from the central control unit. Therefore, in the case of the building having many air conditioners, the operation of the control system tended to become uneconomical and unsafe.